Electrochemical actuator

Abstract

An electrochemical actuator system includes a membrane electrode assembly coupled to a source of electrical energy. The membrane electrode assembly includes a proton-exchange membrane disposed between a first electrode and a second electrode. A first chamber is located on a first side of the membrane electrode assembly and is configured to hold a gas generated by applying electrical energy to the first electrode of the membrane electrode assembly. The membrane electrode assembly and the first chamber are sealed to inhibit fluid communication with the surrounding ambient environment. The chamber includes a diaphragm deformable in response to a change in an amount of the gas in the first chamber. A deformation of the diaphragm in response to the change in the amount of the gas in the first chamber causes a movement of an actuating member coupled to the diaphragm.

1 . An electrochemical actuator system comprising:
 a membrane electrode assembly coupled to a source of electrical energy, said membrane electrode assembly comprising a proton-exchange membrane disposed between a first electrode and a second electrode;   a first chamber located on a first side of said membrane electrode assembly and configured to hold a gas generated by applying electrical energy to said first electrode of said membrane electrode assembly, said membrane electrode assembly and said first chamber sealed to inhibit fluid communication with the surrounding ambient environment;   said first chamber comprising a diaphragm deformable in response to a change in an amount of the gas in said first chamber, wherein a deformation of said diaphragm in response to said change in said amount of the gas in said first chamber causes movement of an actuating member coupled to said diaphragm.   
     
     
         2 . The system of  claim 1  wherein said chamber comprises an opening to allow said diaphragm to expand outwardly in response to an increase in an amount of the gas in said diaphragm. 
     
     
         3 . The system of  claim 1  wherein said actuating member comprises a plunger driven by a deformation of said diaphragm caused by said change in said amount of the gas. 
     
     
         4 . The system of  claim 3  wherein said plunger actuates a mechanical device in response to said change in said amount of the gas. 
     
     
         5 . The system of  claim 1  wherein the application of electrical energy to said membrane electrode assembly causes electrolysis of water present on said membrane electrode assembly (MEA) to cause the gas to flow to said first chamber to deform said diaphragm. 
     
     
         6 . The system of  claim 1  wherein the application of electrical energy to said membrane electrode assembly causes a depletion of O 2  on a first side of said membrane and a creation of O 2  on a second side of said membrane electrode assembly opposite said first side, said O 2  creation resulting in a flow of the gas to said first chamber to deform said diaphragm. 
     
     
         7 . The system of  claim 1  wherein said chamber comprises a first chamber and further comprising a second chamber located on a second side of said membrane electrode assembly and configured to receive a second gas generated by the application of electrical energy to said membrane electrode assembly. 
     
     
         8 . The system of  claim 7  wherein said second chamber comprises a second diaphragm deformable in response to a second change in a second amount of said second gas in said second chamber, wherein a second deformation of said second diaphragm in response to said second change in said second amount of said second gas in said second chamber causes movement of a second actuating member. 
     
     
         9 . The system of  claim 7  further comprising a compression plate contacting said membrane electrode assembly and a cap plate, wherein said second chamber comprises a seal between said compression plate and said cap plate, said seal inhibiting passage of the second gas from said second chamber to the surrounding ambient environment. 
     
     
         10 . The system of  claim 9  wherein said seal is configured to inhibit passage of the second gas to the surrounding ambient environment up to a leakage pressure, said leakage pressure being greater than a desired operating pressure of the system and being less than a pressure causing mechanical damage to said system, said seal allowing the second gas to pass said seal toward the surrounding ambient environment at said leakage pressure. 
     
     
         11 . The system of  claim 9  wherein said compression plate is coupled to said membrane electrode assembly to hold said membrane electrode assembly, said compression plate comprising passages to allow the second gas to pass to said second chamber, said cap plate comprising an outermost extent of said system, said compression plate and said cap plate monolithic relative to each other, and said compression plate and said cap plate having interior surfaces bounding said second chamber. 
     
     
         12 . The system of  claim 11  wherein said cap plate further comprises a pressure relief mechanism configured to release the second gas in response to a pressure of the second chamber reaching a leakage pressure, said leakage pressure being greater than a desired operating pressure of the system and being less than a pressure causing mechanical damage to said pressure relief mechanism, said pressure relief mechanism configured to allow the second gas to pass toward the surrounding ambient environment at said leakage pressure. 
     
     
         13 . The system of  claim 12  wherein said pressure relief mechanism comprises a seal configured to allow the second gas to pass said seal in response to a pressure of the second chamber reaching said leakage pressure. 
     
     
         14 . The system of  claim 1  wherein said membrane electrode assembly is received between a first compression plate and a second compression plate, said first compression plate comprising a first seal portion and a second seal portion, said first seal portion holding said membrane electrode assembly and inhibiting movement of the gas past said first seal toward the surrounding ambient environment, said second seal portion extending around a perimeter of said membrane and said second seal portion configured to inhibit a passage of water from said membrane past said second seal toward the surrounding ambient environment. 
     
     
         15 . The system of  claim 1  further comprising two compression plates coupled to said membrane electrode assembly to hold said membrane electrode assembly under compression, said compression plates coupled to said membrane electrode assembly by overmolding of plastic around said membrane electrode assembly. 
     
     
         16 . The system of  claim 15  wherein said plastic holds said membrane electrode assembly in compression. 
     
     
         17 . The system of  claim 1  wherein said diaphragm is moveable such that said diaphragm expands when the change in the amount of the gas in said first chamber is an increase in the amount of the gas and said diaphragm retracts when the change in the amount of the gas in said first chamber is a decrease in the amount of the gas. 
     
     
         18 . A method for moving an actuator comprising:
 providing a membrane electrode assembly coupled to a source of electrical energy, the membrane electrode assembly comprising a proton-exchange membrane disposed between a first electrode and a second electrode;   applying electrical energy to the membrane electrode assembly to generate gas received by a first chamber located on a first side of the membrane electrode assembly;   sealing the membrane electrode assembly and the first chamber to inhibit fluid communication with a surrounding ambient environment; and   deforming a diaphragm in response to a change in an amount of the gas in the first chamber caused by the gas generated by applying the electrical energy and the deformation of the diaphragm causing movement of an actuating member coupled to said diaphragm.   
     
     
         19 . The method of  claim 18  wherein the actuating member comprises a plunger driven by the deformation of the diaphragm caused by the change in the amount of gas. 
     
     
         20 . The method of  claim 18  wherein the applying the electrical energy to the membrane electrode assembly causes electrolysis of water present on the membrane to cause the gas to flow to the chamber to deform the diaphragm. 
     
     
         21 . The method of  claim 18  wherein water required at an anode for electrolysis diffuses from a cathode side of the membrane electrode assembly. 
     
     
         22 . The method of  claim 18  further comprising a second chamber located on a second side of the membrane electrode assembly relative to the first chamber, the second chamber receiving a second gas generated by the application of the electrical energy to the membrane. 
     
     
         23 . The method of  claim 22  further comprising the second gas passing a seal at a leakage pressure, the leakage pressure being greater than a desired operating pressure of the system and being less than a pressure causing mechanical damage to the seal. 
     
     
         24 . The method of  claim 20  wherein the seal is configured to leak at a pressure greater than a desired operating pressure of the system and less than a pressure causing mechanical damage to the system. 
     
     
         25 . The method of  claim 18  further comprising the first gas passing a seal at a leakage pressure, the leakage pressure being greater than a desired operating pressure of the system and being less than a pressure causing mechanical damage to the system. 
     
     
         26 . The method of  claim 22  further comprising moving a second diaphragm in response to an increase in an amount of the second gas received in the second chamber and generated by the application of electrical energy. 
     
     
         27 . The method of  claim 18  further comprising receiving the membrane electrode assembly between a first compression plate and a second compression plate, and wherein the sealing comprises locating a first seal portion between the first plate and the membrane to hold the membrane electrode assembly and to inhibit movement of a gas past the first seal toward the surrounding ambient environment. 
     
     
         28 . The method of  claim 27  further comprising locating a water seal between the membrane electrode assembly and the first compression plate and extending the water seal around a perimeter of the membrane to inhibit movement of water past the water seal to the surrounding ambient environment. 
     
     
         29 . The method of  claim 18  further comprising overmolding two compression plates on opposite sides of the membrane electrode assembly to maintain the membrane electrode assembly under compression. 
     
     
         30 . The method of  claim 18  wherein the change in the amount of the gas in a first chamber comprises an increase in the amount of the gas to cause an extension of the diaphragm away from the membrane electrode assembly. 
     
     
         31 . The method of  claim 18  wherein the change in the amount of the gas in a first chamber comprises a decrease in the amount of the gas to cause a retraction of the diaphragm toward the membrane electrode assembly. 
     
     
         32 . The system of  claim 1  wherein said diaphragm comprises a resilient diaphragm configured to elastically expand when the change in the amount of the gas comprises an increased amount of gas and to elastically retract when the change comprises a decreased amount of the gas. 
     
     
         33 . A method for supplying pilot pressure comprising:
 providing a membrane electrode assembly coupled to a source of electrical energy, the membrane electrode assembly comprising a proton-exchange membrane disposed between a first electrode and a second electrode;   applying electrical energy to the membrane electrode assembly to generate a gas received by a first chamber located on a first side of the membrane electrode assembly;   sealing the membrane electrode assembly and the first chamber to inhibit fluid communication with a surrounding ambient environment; and   providing fluid communication between the first chamber and a pilot pressure operated device.   
     
     
         34 . A method for use in providing oxygen as a working fluid to at least one chamber of an electrochemical actuator system:
 providing a membrane electrode assembly coupled to a source of electrical energy, the membrane electrode assembly comprising a proton-exchange membrane disposed between a first electrode and a second electrode;   providing a first gas storage chamber located on a first side of the membrane and a second gas storage chamber located on an opposite side of the membrane;   the first chamber and the second chamber being sealed from an outside ambient environment such that the first chamber and the second chamber leak at a preset gas leak pressure, the first chamber being about a same size as the second chamber;   applying electrical energy to the membrane electrode assembly to cause electrolysis of water present on the membrane to generate hydrogen gas received by the first chamber and to generate oxygen gas received by the second chamber, such that an amount of the hydrogen held in the first chamber is about equal to an amount of the oxygen held in the second chamber.   
     
     
         35 . The method of  claim 34  further comprising reversing the electrical energy to cause reverse electrolysis to combine the hydrogen in the first chamber with the oxygen in the second chamber to form water such that the hydrogen is substantially completely consumed.